The invention relates to a device and a corresponding method for rapid image data transfer in printing presses.
A device of that general type and a corresponding method are disclosed in U.S. Pat. No. 6,029,576. In that regard, flexible finishing of a printed product is made possible, and an ability to allocate the printing presses used in a print shop is achieved. For that purpose, in the prepress area, there are, amongst others, a computer and two storage units. Image-specific data are stored in the first storage unit of the computer, and printing control-specific image data are stored in the second storage unit. After a concrete job has been allocated to a specific printing press in the print shop, a selection is made from print control-specific image data with which the job can be controlled optimally on the allocated printing press. The mutually associated image-specific and print control-specific image data are then transmitted jointly, via a local network and a bus system, respectively, on which a plurality of imaging systems, that include a raster image processor, hereinafter referred to by the first initials thereof as RIP, a press computer and a printing press erected in the machine room, depend, to an RIP of a corresponding printing press for imaging and control.
Furthermore, European Patent Application EP 0 755 786 A1 discloses a device for controlling a printing press, in particular a sheet-fed offset printing press. The device has a plurality of computers with memories. The individual computers are connected to one another via a bus system constructed as a network, e.g., a CAN-bus. Via the bus and an interface provided as a special connection, a programming unit coupled therewith can realize the changeover of the computer connected to the bus from a state corresponding to normal press operation into a programming state.
Furthermore, it is generally known that, in digital printing presses, during the imaging operation, the separation data previously generated by the RIP are transmitted to the laser imaging units. In order to be able to prevent the imaging from being terminated, a data transfer with a continuous data rate matched to the respective imaging speed and system configuration is required. Consequently, in the case of digital printing presses, the requirement for the overall data rate increases with an increasing number of printing units, because there is an image-setting or imaging unit in each printing unit. Since the RIP according to the state of the prior art is generally incapable of making the required overall data rate available during the imaging, intermediate storage of the separation data is required. Thus, the data is initially copied from the RIP to one or more intermediate memories and then read from the intermediate memories at the required data rate during the imaging. A significant feature of a universal imaging system, in this regard, is being easy to scale. The system must accordingly be suitable for meeting the respective requirements relating to smaller and larger press configurations to the same extent.
In imagesetting or imaging systems which are presently available, hard disks are used as storage media for buffering the separation data. Since hard disks are sensitive to shocks, they are integrated into a separate storage unit in a switch cabinet and not within the printing press. Therefore, no direct access from the imaging unit to the hard disks is possible. The provision of a special storage unit, which is capable of supplying up to six imaging units with image data, has become known heretofore. On the input side, that unit has an SCSI interface, via which the separation data is transmitted to the storage unit. On the output side, there are six proprietary optical bus systems for transmitting the data to the imaging units. The internal electronics are processor-based and are able to drive up to six hard disks, which can be fitted as desired. A disadvantage of that configuration is that it is difficult to scale with regard to costs and performance. That is because the configuration is optimal only in the case of presses having exactly six or exactly twelve printing units. For the case of a configuration deviating therefrom, components are in the system which are not required with respect to performance, and result in unnecessary costs. Since the imaging units have no direct access to the hard disks, a further computer system is always additionally required for assuming the management of the hard disks and the data transfer to the imaging units.
A further approach to a better scaled printing system is by providing a computer system with a hard disk for each printing unit. The connection of the RIP to the computer systems is realized or implemented via an Ethernet interface, and each imaging unit is connected individually to the appertaining computer system via a serial bus line. In that regard, the computer system and the PC respectively send the imaging data to the respective printing unit. Although that modified embodiment meets the requirements with regard to scalability, that advantage is opposed by relatively high costs for the requisite computer systems.
It is accordingly an object of the invention to provide a device and a corresponding method for fast image transfer in printing presses, which overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and with which it is possible for an intermediate storage of the image data to be scaled easily with regard to costs and performance.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a device for fast image data transfer in at least one printing press having at least one RIP. The image data transfer device includes a data manager to which image data is supplied, at least one storage unit and at least one imaging unit. A bus system is provided for connecting the at least one storage unit both to the at least one data manager for intermediate buffering of the image data, and to the at least one imaging unit for setting an image. The at least one imaging unit serves for communicating with the at least one storage unit, and for reading the image data directly from the at least one storage unit.
In accordance with another feature of the invention, the at least one imaging unit includes at least two imaging units serially connected to one another and to the at least one storage unit by the bus system.
In accordance with a further feature of the invention, the at least one imaging unit includes at least two imaging units connected via the bus system to the one storage unit, and jointly accessible thereto via the bus system.
In accordance with an added feature of the invention, the bus system includes a plurality of data lines. A plurality of the imaging units are connected to a plurality of the storage units via only one individual data line of the bus system.
In accordance with an additional feature of the invention, the at least one imaging unit is capable of reading the image data directly from the at least one storage unit via the bus system.
In accordance with yet another feature of the invention, the at least one data manager is capable of writing the image data into more than the one storage unit via the bus system.
In accordance with yet a further feature of the invention, the at least one data manager is capable of writing the image data into all of the storage units via the bus system.
In accordance with yet an added feature of the invention, the components of the image data transfer device are capable of utilizing at least one of the groups consisting of different transmission media and standards of the bus system.
In accordance with yet an additional feature of the invention, the at least one storage unit includes at least two storage units assigned to one imaging unit.
In accordance with still another feature of the invention, the at least one data manager serves for defining an assignment of the at least one storage unit to the at least one imaging unit and for writing appropriate image data into the respectively defined storage unit.
With the objects of the invention in view, there is also provided a method for fast image data transfer in printing presses. The method includes using at least one data manager for writing image data obtained from at least one RIP via a bus system into at least one storage unit for intermediate buffering of the image data. At least one imaging unit connected to the at least one storage unit communicates via the bus system with the at least one storage unit. The image data, which is stored in the at least one storage unit, is directly read for setting an image.
Through the use of the foregoing construction of the device according to the invention, a system architecture which can be scaled easily with regard to costs and performance is provided, that affords intermediate buffering of the image and separation data, respectively, for an imaging system for digital printing presses and CTP systems. The invention is based on storage media which use the same bus interface as the imaging units and to which all the bus subscribers are accessible via this bus system. Accordingly, both the computer designated as the data manager and the respective imaging units are accessible to these storage media via one and the same bus system. Before setting an image, the data manager copies the separation data received from the RIP to the respective storage medium. During the imaging, the data is read from the storage medium again by the imaging units. As a result, the imaging units are directly accessible to the storage media without having to take the circuitous route via a further computer system. Within the imaging system, there is only one bus system, via which the separation data is both written and read.
Provision is advantageously made, if possible, for all of the imaging units to be connected to the storage units via only a single individual data line of the bus system. This construction is particularly cost-effective and, in addition, offers the advantage that there is no fixed association between the printing units and the storage units. Thus, even shortly before the imaging operation, a change in the data assignment is possible without recopying the respective image and printing data. The system and, in particular, the individual data line, in this regard, must be suitable for the correspondingly high data rates which occur.
According to a preferred embodiment, at least two storage units are assigned to one imaging unit. In this regard, the higher data throughput of the overall configuration as compared with a configuration having only one hard disk per imaging unit is advantageous. In addition, subsequent expansion of the storage capacity of the system is facilitated in this embodiment. Furthermore, the fail safety of the system is increased by storage units which, from time to time, are redundant.
In order to be able to adapt the configuration optimally to the respective requirements with regard to performance and costs, provision can be made for the components to be connected to one another via a common bus system but to make use of different respective transmission media and standards of a bus system (e.g. copper cable, glass fiber). Provision can also be made for obtaining access to the storage unit on the data manager side and on the imaging side via different bus systems.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a device and a corresponding method for fast image data transfer in printing presses, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.